polygraph

There is a sickness in our minds, and it runs deep. It is a desire to force the facts to fit our opinions, rather than force our opinions to fit the facts. This madness is especially dangerous when the facts in question are related to crimes and justice. Our institutions have a terrible tendency to force people to appear guilty instead of determining whether or not they actually are guilty.

One area where this tendency manifests is in the way cops interrogate suspects. The Reid Technique is currently popular among American law-enforcement agencies as a way to get suspects to confess. It is a powerful technique, with a proven track record of getting people to confess to crimes that they could not possibly have committed. FalseConfessions.org describes how this can happen on this page. Here’s a typical example:

Martin Tankleff had just turned 17, when he found his mother brutally murdered and his father clinging to life after being attacked. After calling 911, he was immediately taken to police headquarters and underwent harsh interrogation by homicide investigators. He was told that his hair was found in his mother’s dead fingers and that his father awoke from his coma to identify young Martin as his attacker. Although he was never Mirandized and maintained his innocence, police finally convinced Marty that he must have blacked out. Confused and scared, Marty came to believe his interrogators that he blacked out and committed the crime. Although not one bit of forensic evidence linked Marty to the crime scene, he was convicted and sentenced to fifty years in prison. After serving close to 18 yeas, his conviction was finally overturned in 2007. (see www.Martytankleff.org)

A recent scientific study, reported here by the Star, concluded that it was extremely easy to get people to believe themselves guilty of a crime: 70 percent of participants in a study were persuaded that they were guilty of a crime, with only minimal suggestions from the researchers. To make matters worse, some of the fooled participants became so convinced of their own guilt that they could not be re-persuaded to believe themselves innocent, even when the researchers revealed the ruse! The scientists prematurely ended the study, frightened of their terrible discovery, but the techniques they used remain common practice in police departments all across America. In fact, the Reid Technique was first developed in 1942, so we have several decades’ worth of false confessions on the books. How many people have already died, wrongfully convinced of their own guilt? I can only guess.

It’s worth noting, as Brian Gallini does in this paper, that the Reid Technique was based off of polygraph techniques – the so-called “lie detector”, which happens to be based on a pack of lies. Gallini observes that the polygraph’s credibility was already in question in 1942, so the Reid technique was in trouble from the start, and yet it has become common practice, in spite of evidence that it does not work! And speaking of the polygraph, that one hasn’t gone away, either: California is now requiring paroled sex offenders to take the test. Apparently, it is too much to ask that our governments refrain from using methods that routinely incriminate innocent people.

The Reid Technique and the polygraph are not alone in the government’s arsenal of methods for conjuring up guilt. Let us not forget that our forces are fighting a War on Terror, and to fight such a war, they must sometimes use “enhanced interrogation techniques” to get critical information out of terrorist suspects. Torture, in other words. But does torture work? There is precious little evidence in its favor. There are many who claim that it is effective, but, as former FBI agent Ali Soufan notes in this op-ed, they have a track record of lying. The US Army’s own field manual on intelligence interrogation notes that “the use of force is a poor technique, as it yields unreliable results, may damage subsequent collection efforts, and can induce the source to say whatever he thinks the interrogator wants to hear”. Alas, it is that final property of torture – that it can induce someone to say whatever the interrogator wants to hear – that makes it so useful to its practitioners. When you want to force the facts to fit your opinion, waterboarding people into submission seems like a great idea. (For a good examination of this mad way of thinking, read this piece by Major Anthony Milavic.)

There is one other information-gathering technique that I wish to discuss: mass surveillance. This one stands out from the others I’ve mentioned because it’s so much less personal, and it doesn’t appear to force anyone to lie. And yet, it suffers from the same failures as torture, polygraphing, and Reid Technique: it’s terrible at getting the truth and great at creating the appearance of guilt.

In defense of the first assertion, consider this post from WashingtonsBlog, in which the author notes (among other good points) that even before the 9/11 attacks, there was plenty of mass surveillance going on, and plenty of data being gathered about the people who would eventually carry out the attacks, but none of that data was able to prevent the attack. Why not? The author quotes from this piece by Nassim Taleb: “Big data may mean more information, but it also means more false information.” Perhaps this is why the NSA’s bulk metadata collection program has failed to prevent even a single terrorist attack.

But there’s another danger that Snowden didn’t mention that’s inherent in the government’s having easy access to the voluminous data we produce every day: It can imply guilt where there is none. When investigators have mountains of data on a particular target, it’s easy to see only the data points that confirm their theories — especially in counterterrorism investigations when the stakes are so high — while ignoring or downplaying the rest…

Mayfield had converted to Islam after meeting his wife, an Egyptian. He had represented one of the Portland Seven, a group of men who tried to travel to Afghanistan to fight for al Qaeda and the Taliban against U.S. and coalition forces in a child custody case. He also worshipped at the same mosque as the militants. In the aftermath of 9/11, these innocent associations and relationships, however tangential, were transformed by investigators into evidence that Mayfield wasn’t a civic-minded American, but a bloodthirsty terrorist intent on destroying the West…

FBI agents broke into Mayfield’s home and law office. They rifled through documents protected by attorney-client privilege, wiretapped his phones, analyzed his financial records and web browsing history, and went through his garbage. They followed him wherever he went. Despite all this, the FBI never found a smoking gun connecting him to Madrid. They did, however, find Internet searches of flights to Spain and learned that he once took flying lessons. To FBI agents already convinced of his guilt, this was all evidence of Mayfield’s terrorist heart…

While it may seem like there were a freakish number of coincidences here, when the FBI was confronted with evidence that demonstrated Mayfield’s innocence, they twisted it to support their original theory of his guilt. With no evidence that Mayfield had traveled internationally for years — his passport had expired, and the last record of foreign travel was during his military service in 1994 — the FBI simply concocted the theory that he must have traveled overseas as part of this terrorist conspiracy under a false identity…

Because of mistakes made by the FBI — they left shoe prints in the carpet of the Mayfields’ home and broke in one time when Mayfield’s son was home alone — Mayfield concluded he was under surveillance by federal authorities. Paranoia set in. When driving, he would look to see if someone was following him home or to the office. The FBI took his skittishness as more evidence of his guilt.

There is a saying, which some attribute to Cardinal de Richelieu: “Qu’on me donne six lignes écrites de la main du plus honnête homme, j’y trouverai de quoi le faire pendre.” Translated: “If you give me six lines written by the hand of the most honest of men, I will find something in them which will hang him.” (Hat tip to Cory Doctorow for telling me about that quote) In other words, it’s easy to make people look guilty. And if six lines aren’t enough, then collect six hundred, or maybe six million. That is what mass surveillance offers: enough noise to cherry-pick any data we want, and invent guilt in any target we choose.

The polygraph does not actually detect lies, because nothing can detect lies. Instead, it monitors and records reactions in the body of the person being tested. It checks how you’re breathing, how much you’re sweating, how fast your heart is beating, and so on. The theory is that when you tell a lie, your body reacts in a certain way, and that by detecting those reactions, the polygraph can determine when you’re trying to deceive the questioner. A seductive idea; to be able to sniff out a lie, right at its source! What power, and what convenience!

As the FAS put it, “the polygraph detects deception at a rate better than chance, but with error rates that could be considered significant.” Not exactly a ringing endorsement. And then they give us this to chew on:

One area of special concern in personnel security screening is the incorrect identification of innocent persons as deceptive. All other factors being equal, the low base rates of guilt in screening situations would lead to high false positive rates, even assuming very high polygraph validity. For example, a typical polygraph screening situation might involve a base rate of one guilty person (e.g., one person engaging in unauthorized disclosure) out of 1,000 employees. Assuming that the polygraph is 95 percent valid, then, the one guilty person would be identified as deceptive but so would 50 innocent persons. The predictive validity would be about 2 percent. Even if 99 percent polygraph validity is assumed, there would still be 10 false positives for every correct detection of a guilty person.

10 people, falsely declared liars, for every liar found. And that’s for a 99 percent validity. Look again at the estimates for actual validity, and do the math for yourself.

Happily, some folks have paid attention, and have limited or banned the use of polygraphs. Here in the U.S., defendants and witnesses cannot be forced to take a polygraph test, and several states forbid employers from using the test on their employees. Unfortunately, government agencies are still allowed to polygraph their employees, so the test is still used as a pre-employment screen by the FBI and the CIA.

Let me emphasize the oddness of this. The polygraph is inaccurate enough that courts can’t force it on witnesses and private employers can’t force it on their would-be employees, yet the CIA and the FBI – two agencies who really ought to have top standards for using reliable tests – still use it to screen their employees. Two powerful agencies, whom we are asked to trust with our safety and security, are totally committed to using a bad test.

Sadly, this kind of behavior is typical. Whether it’s the bomb detector used by the UK and Iraqi government (among others) that’s no better than a dowsing rod, interrogation techniques that can compel anyone to confess to anything (never mind whether or not they actually did it), or the NSA’s habit of collecting huge amounts of data that don’t actually help prevent any attacks, the high and mighty have a proven track record of stupidity. Keep that in mind when they ask you to trust them and give them more power.